Storage-battery electrode and process of making it.



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WILLIAM MORRISON, OF DES MOINES, IOWA.

STORAGE-BATTERY ELECTRODE AND PROCESS OF MAKING I1;

No Drawing.

Specification of Letters Patent. Application filed September 29, 1911.

' Patented Nov. 1a, lei-i. Serial No. 651,962.

To all whom it may concern.

Be it known that I, VVILLIAM MoRRIsoN, a citizen of the United States, residing at Des Moines, in the county of Folk and State of Iowa, have invented certain new and'useful Improvements in Storage-Battery Electrodes and Processes of Making Them, of which the following is a specification.

In accordance with this invention I produce an electrode for storage or secondary batteries, in which the active material is impregnated with and bonded by rubber, specifically vulcanized rubber, in the form of a coherent absorbed skeleton, sponge or film holding enmeshed the particles of the active material;

The preferred proces of making a-positivepole lead peroxid electrode is as follows: An antimonial lead grid or other suitable support and conductor is pasted with a mixture of red-lead, litharge, sulfuric acid and a small amount of an aqueous hydrogen peroXidsolution and allowed to surfaces of the active material are then scraped, as with a sharpedged tool, to remove any glaze or skin and open the surficial pores. The electrode is then dipped'in an aqueous solution of sulfuric acid containing some hydrogen peroxid, and is again allowed to dry, causing the paste to fully swell and come in close contact with the grid. The pasted grid is initially formed by subjecting it to anodic oxidation in an aqueous sulfuric acid solution, is discharged, and is removed from the solution and dried. This formation increases the conductivity of the particles of lead oXid and causes them to come into close electrical contact with each other and with the grid, giving the electrode the maximum conductivity prior to the introduction of the rubber bond, which is a non-conductor. The active material is now impregnated with rubber by submerging the electrode in a dilute solution of rubber, and preferably also sulfur, in carbon disulfid, the solution covering the electrode to a considerable depth, to cause it to enter the pores of the active material. It is allowed to remain in the solution until all air-bubbles cease to rise therefrom, that is until the pores have been filled with the solution. The vessel containing the solution is then quickly emptied and is refilled with pure carbon disulfid, which is allowed to act on the electrode for a minute or two. to remove any excess of rubber adthoroughlyhering to the external surfacesof the active material and grid. The electrode is then removed from the carbon disulfid and is dried. If sulfurv has been dissolved in the rubber solution, the -rubberbond in theelectrode is cured or vulcanized by subjecting the electrode to regulated heat, for example to a temperature of 285 F. in a steam-' jacketed chamber, the rubber retaining its elasticity and better resisting the action of the battery electrolyte. If the rubber solution. contains no sulfur, the bond may be vulcanized by dipping the electrode in a so lution of sulfur chlorid in carbon disuliid. The electrode is finally subjected to prolonged formation until the lead sulfate in the paste is entirely or substantially all cone. verted into'lead peroxid, no lead sulfate binder being requisite in this elect-rode, as in the ordinary one. The pure carbon disulfid employed for washing the electrode is subsequently employed of the rubber solution. p

The'initial formation of the electrode may be omitted and the pasted grid, with the active material swelled and scraped, may be directly put into a weak rubber solution.

for the preparation But thismodified procedure causes a considerable loss of electric current in the sub, sequent formation of the elect-rode.

Electrodes thus treated have a greatly inand may be charged at a rate. Their dural'nlity creased durabilit greatly increased and charge-rate capacity may be still further increased by repeating the treatment, that is by again submerging them in a rubber solution, washing with carbon disulfid and vulcanizing. A rectangular plate measuring six by eight inches which has been subjected to four treatments may be charged at a rate two or three times the normal one, for e2:- ample wit-h a current of 20 amperes. The

rubber bond interpenetrates the active ma terial as an adsorbed skeletomsponge or film, enmeshing the discrete particles of the paste but leaving open pores between them for the battery electrolyte, as distinguished from a binder which is mechanically mixed with the paste before it is applied to the grid and practically fills the spaces between the particles of active material. The thickness and strength of the adsorbed film of rubber vary directly as the number of treatments with the rubber solution.

While the invention has been described in connection with the production of a past-ed electrode, it will be understood that it is also apphcable to electrodes of the Plant type, in which the active material is electrolytically formed from the metal of the electhe rubber solute freed 'from the solvent.

I claimi 1.- 'A storage battery electrode, comprising a body of formed active material interpenei trated with and bonded by an adsorbed skeleton, sponge or film of a desiccated solute of rubber. v p

2. A storage battery electrode, comprising abody of formed active material interpene-, trated with and bonded by an adsorbed skeleton, sponge or film of a desiccated and vulcanized solute of rubber.

3. The process oi making storage battery electrodes, which consists in enmeshing the particles of the active material in an adsorbed skeleton, sponge or film of a desiccated solute of rubber.

4. The process of making storage battery electrodes, which consists in enmeshing the particles of the active material in an adsorbed skeleton, sponge or film of a desiccated and vulcanized solute of rubber.

5.-The process of making lead peroxicl electrodes having a rubber: bond, which consists in initially forming the electrode. filling the pores of the active material with a solution containing dissolved rubber, and eliminating the solvent.

teria l, scraping the 6. The nrocess of making lead peroxid electrodes having a vulcanized rubber bond, which consists in initially forming the electrode, submerging it in a solution containing dissolved rubber, washing the electrode with a solvent of rubber, and vulcanizing the rubber.

T. The process of making lead peroxid electrodes having a rubber bond, which consists n initially forming the electrode, submerglng it in a solutlon containing dissolved rubber, washing the electrode with a solvent of rubber, and again forming the electrode, treating it with a solution of rubber and washing.

8. The process of making pasted lead peroxid electrodes having a rubber bond, which consists in expanding the active material, scraping the surfaces of the active material,- submerging the electrode in a solution containing dissolved rubber, and washing it ina solvent of rubber.

9. The process of making pasted lead peroxid electrodes having a rubber bond, which consists in expanding the active masurfaces of the active material, initially forming the electrode, submerging it in a solution containing dissolved rubber, and washing it in a solvent of rubber.

In testimony whereof I afiix my signature in presence of two witnesses.

WILLIAM MORRISON.

\Vitnesses:

CHARLES H. POTTER, Bonner I. HULSIZER. 

